40ae34194c
detects redundant imports that can be eliminated. for #117772 : In order to facilitate review and modification, split the checking code and removing redundant imports code into two PR.
43 lines
896 B
Rust
43 lines
896 B
Rust
// run-pass
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// Checks that the Fn trait hierarchy rules permit
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// any Fn trait to be used where Fn is implemented.
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#![feature(unboxed_closures, fn_traits)]
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struct S;
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impl Fn<(i32,)> for S {
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extern "rust-call" fn call(&self, (x,): (i32,)) -> i32 {
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x * x
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}
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}
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impl FnMut<(i32,)> for S {
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extern "rust-call" fn call_mut(&mut self, args: (i32,)) -> i32 { self.call(args) }
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}
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impl FnOnce<(i32,)> for S {
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type Output = i32;
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extern "rust-call" fn call_once(self, args: (i32,)) -> i32 { self.call(args) }
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}
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fn call_it<F:Fn(i32)->i32>(f: &F, x: i32) -> i32 {
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f(x)
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}
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fn call_it_mut<F:FnMut(i32)->i32>(f: &mut F, x: i32) -> i32 {
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f(x)
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}
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fn call_it_once<F:FnOnce(i32)->i32>(f: F, x: i32) -> i32 {
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f(x)
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}
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fn main() {
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let x = call_it(&S, 22);
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let y = call_it_mut(&mut S, 22);
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let z = call_it_once(S, 22);
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assert_eq!(x, y);
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assert_eq!(y, z);
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}
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